Method and apparatus of informing a network of change of user equipment capability

ABSTRACT

An embodiment method of informing a network of a change of user equipment capability includes receiving, by a network, a register request message carrying information of new user equipment capability to from a user equipment, analyzing, by the network, the register request message, and storing the information of new user equipment capability for reference by subsequent establishment of a session, stopping a current registration timer on the server side set for the user equipment, initiating a new registration timer on the server side for the user equipment, and sending a response message carrying information of the new registration timer on the server side to the user equipment so as to reset a registration timer on the user side based on information of the new registration timer on the server side in the response message. The capability change is informed to the network in time.

This application is a continuation of U.S. patent application Ser. No.12/948,875, filed on Nov. 18, 2010, which is a continuation of U.S.patent application Ser. No. 11/630,427, filed on Dec. 27, 2007, andissued as U.S. Pat. No. 7,860,501, which is a continuation ofInternational Application No. PCT/CN2005/000997, filed on Jul. 7, 2005,which claims priority to Chinese Patent Application No. 200410070235.4,filed on Jul. 30, 2004, all of which are incorporated herein byreference in their entireties.

TECHNICAL FIELD

The present invention relates to a network using SIP protocol, includingan IP multimedia subsystem (IMS) network, and more particularly, thepresent invention relates to an apparatus and method of informing thenetwork of a change of user equipment capability when the user equipmentcapability changes in the IMS network.

BACKGROUND

With development of broadband network, mobile communications are notonly limited to traditional voice communication. Multimedia service,which combines a plurality of media types, such as audio, video, photoand text, etc., will be developed gradually, and through combinationwith Presence (presence service), SMS (short message service), WEBbrowsing, location information, PUSH (push service), file sharing andother data services, it can satisfy various requests of users, e.g.:

message services: instant message and chat room, multimedia shortmessage;

video services: entertainment, multimedia information, dailycommunication;

electronic commerce: product catalog, search engine, cart, order formmanagement, payment;

game: single game, group game;

location service: searching for people, guiding, alarming;

personal assistant: address book, calendar, bookmark management, filestorage, event reminder, E-mail.

Under promotion of various applications, 3GPP (3^(rd) GenerationPartnership Project), 3GPP2 (3^(rd) Generation Partnership Project 2)and other standard organizations all successively launch an IMS (IPMultimedia Subsystem) architecture, with a purpose to implement variousmultimedia applications using a standard open structure in a mobilenetwork and provide more choices and wonderful feelings.

In 3GPP Release 5 (R5) phase, an IMS is introduced, which is added to apacket domain network and includes such function entities as CSCF (CallSession Control Function), MGCF (Media Gateway Control Function), MRF(Multimedia Resource Function) and HSS (Home Subscriber Server), etc.The CSCF can also be divided into three logic entities, which are S-CSCF(Service CSCF), P-CSCF (Proxy CSCF) and I-CSCF (Inquiry CSCF), whereinS-CSCF, as a service switching center of IMS, executes session control,maintains session state, manages user information, and generatescharging information, etc.; P-CSCF, as an access point for a terminaluser to access the IMS, finishes subscriber register, and is responsiblefor QoS control and security management etc.; I-CSCF is responsible forintercommunications between IMS domains, manages S-CSCF allocation,hides network topology structure and configuration from the outside, andgenerates charging data, etc. MGCF controls gateways and implementsintercommunication between IMS network and other networks; MRF providesmedia resources, such as receiving/broadcasting voices, coding/decoding,establishing multimedia conference bridge; HSS is a user database, whichstores subscription data and configuration information of IMS users,etc.

Because IMS network structure has no relation with a lower-layer bearernetwork, the IMS network defined by 3GPP can be applied to other packetnetworks besides the packet domain network defined by 3GPP, such as thepacket network defined by 3GPP2, WLAN network, and NGN network, etc.,independent of user terminal type and access network type. Thereforehere IMS is not limited to be used in networks and applications relatedto 3GPP, but can be used in services and applications of other types ofaccess networks and bearer networks.

Session Initiation Protocol (SIP): SIP is an IP phone signaling protocolproposed by IETF (Internet Engineering Task Force). As is implicated byits name, SIP is used to initiate a session, can control establishmentand termination of a multimedia session joined by many participants, andcan dynamically adjust and modify session attributes, such as sessionbandwidth request, transmitted media types (voice, video and text,etc.), media coding/decoding formats, support for multicast and unicast,etc. In an IMS, SIP protocol is used as a signaling control protocol ofan IP multimedia session.

A new framework of AAA—Diameter protocol:

AAA, i.e. Authentication, Authorization and Accounting, up to today, isalways a foundation based upon which network carriers run and managenetworks. With development of AAA, a new framework Diameter technologyhas come into being.

Diameter protocol suite includes a base protocol (Diameter BaseProtocol) and various application protocols. The base protocol providesthe lowest requirements of the AAA protocol for functions that must beachieved by all of Diameter network nodes, including negotiation ofability between the nodes, receiving and forwarding of Diameter messagesand real time transmission of charging information, etc. The applicationprotocols adequately utilize a message transmission mechanism providedby the base protocol and standardize functions and special messagecontents of corresponding nodes to implement AAA of applicationservices.

In the IMS, Diameter protocol is used to transmit correspondinginformation on a Cx interface between HSS and I-CSCF and between HSS andS-CSCF.

Home Subscriber Server (HSS):

HSS, the most important database for each user, stores all informationrelated to subscription and is used to support processes on a call or asession by each network entity, specifically including: user ID, numberand addressing information, user security information, user locationinformation and user profile information, etc. Home network can have oneor several HSSs depending on the number of mobile subscribers, capacityof network devices and detailed networking situations. There areinterfaces between HSS and several network entities, in which aninterface between HSS and I-CSCF or between HSS and S-CSCF is a Cxinterface.

In future multimedia applications, user equipments will be capable ofsupporting several media types, such as audio, video, text and image,etc., and each media type can support more than one coding/decodingformat. Accordingly, user equipments may need to have various built-inor external devices. For a mobile phone, since its smaller size, Plugand Play devices are used more often, such as video camera, potablemobile store device, MP3, external keyboard, etc. Presence or absence ofeach of these devices means whether a terminal user can use a certainmultimedia application, for example, the presence of video camera meansthat the user can initiate a video call. Even if the device is not aPlug and Play device, it may need to be configured by users to beenabled or disabled; for example, a built-in recoding function, infraredfunction etc., is enabled through special combination of keys on akeyboard.

Since these devices come into effect immediately once they are used,from the moment they take effect, the capability of the user equipmentchanges. A method of informing the network of the changed capability ofthe user equipment in time is needed, so that the network can know thecapability of the user equipment immediately, and further determinewhether to accept some service requests from the user equipment andwhether to accept some service requests from other user equipments whenthe user equipment is called.

At present, in an IMS network, a negotiation on capability of a UE (userequipment) is implemented through a process of establishing andmodifying an SIP session. When a UE (or mobile terminal) initiates toestablish an SIP session, an INVITE message is used to bring thecapabilities of a calling UE to the network and an opposite end UE. Eachnetwork node related to the session and the opposite end UE need todetermine whether to accept the session establishment according to theirrespective support capabilities and support capability of the callingUE, for example, a P-CSCF (including a calling P-CSCF and a calledP-CSCF) determines whether to allow establishment of the SIP sessioninitiated by the calling UE or called UE according to a local strategy,and S-CSCF (including a calling S-CSCF and a called S-CSCF) determineswhether to allow establishment of the SIP session initiated by thecalling UE or called UE according to a local strategy or the subscriberprofile downloaded from the HSS, while the called UE determines whetherto accept the request of establishing the session according to its owncapability. If the capability of the calling UE or called UE has changedbefore completion of the INVITE session, for example, a PnP device isplugged/unplugged or a built-in function is enabled/disabled etc., therelated UE can modify the establishing SIP session by sending an UPDATEmessage bearing information of the changed capability of the UE and anetwork node and opposite end UE, after receiving the UPDATE message,will renegotiate the session establishment according to the changedcapability of the UE and if the negotiation succeeds, the new capabilityof the UE is used to perform the session, or if the negotiation fails,the old capability of the UE is still used to establish the session. Ifthe INVITE session has finished, an SIP session has been establishedsuccessfully and a real service data transmission has been startedbetween the calling UE and called UE or the calling UE and an AS(Application Server), and at this time the capability of the calling UEor called UE changes, for example, a PnP device is inserted or a certainbuilt-in function is enabled to be used in the present service, aRE-INVITE message can be reinitiated, bearing information of the changedcapability of the terminal, and the present session is renegotiatedaccording to a re-negotiation process similar to the negotiation processof INVITE. After the re-negotiation succeeds, the new capability of theterminal is used to perform the service and the old negotiation resultis deleted, or if the negotiation fails, the old negotiation result isstill used to perform the service.

Besides the method of informing the network and opposite end UE of theuser equipment capability during the session establishing and modifyingprocess, when each UE establishes contact with the IMS network for thefirst time, that is, when it initiates an IMS register, the capabilityinformation of the user equipment can be encapsulated in a REGISTERmessage and sent to the network, and is stored in an S-CSCF fordetermining subsequent processes by the S-CSCF when the S-CSCF receivesa request of establishing or modifying a SIP session subsequently.

SUMMARY OF THE INVENTION

The present invention provides a method of informing a network of achange of user equipment capability.

A method of informing a change of user equipment capability includes:the user equipment stops a registration timer on the user side setcurrently when the user equipment capability changes; a register requestmessage carrying information of new user equipment capability is sent tothe network; the network analyzes the register request message andstores the information of the new user equipment capability forreference by subsequent establishment of a session; a currentregistration timer on the server side set for the user equipment isstopped; a new registration timer on the server side for the userequipment is initiated; a response message carrying information of thenew registration timer on the server side is sent to the user equipment;and a registration timer on the user side is reset based on informationof the new registration timer on the server side in the responsemessage.

Compared to the prior art, the present invention may have the followingadvantages:

Through the use of the present invention, a re-register process can beinitiated when the terminal capability changes by using an existingregister flow and increasing the number of trigger points of there-register process, and a network can be informed of the newestcapability change of a user terminal, so that the network can utilizethe new capability information of the user terminal to negotiate asession establishment process in a session process thereafter, whichavoids additional messages for re-negotiating capabilities of bothparties after a session begins, and therefore decreases the additionalmessage intercommunication, shortens intercommunication time required bya session establishment, optimizes the implementing process, andlightens network loads.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a flow chart of a method of informing a network of a userequipment capability change according to an embodiment of the presentinvention.

FIG. 2 is a detailed flow chart of the embodiment of FIG. 1.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

User equipment capability is an attribute of a user equipment and isused to indicate possibility of the user equipment creating orprocessing a certain specific type of message content and can benegotiated during certain session processes. Some examples of basiccapabilities are shown as follows: whether to support audio, video,message, automatic apparatus, mobility, specific SIP method (for exampleINVITE, CANCEL, etc.), PRESENCE state and so on, types of supportedlanguages (for example English, Chinese, etc.) and basic categories ofdevice (for example desktop, laptop or mobile phone, etc.). When acertain capability value changes from zero to one, or from one to zero,the user equipment capability changes.

The embodiment of present invention provides a method, which is used toresolve the problem of how to inform corresponding nodes in a network ifuser equipment capability changes when a UE has registered with thenetwork but not established a session yet. Through an immediatere-register process initiated by the UE, the network can be informed ofthe newest capability information of the UE in real time, and thereforeit can use the newest capability information to negotiate anestablishing session process during a subsequent session process,avoiding additional messages required to renegotiate the two partiescapabilities after the session starts so that the additionalintercommunication messages can be decreased, and the intercommunicationtime for establishing the session can be shortened. So the presentinvention may optimize the implementing process and lighten the networkload.

Please refer to FIG. 1, when a UE wants to get to contact with an IMSnetwork or SIP network, a User Agent in the UE will initiate a registerprocess, and send a register request message, such as a Register, to afunction entity, such as a Registrar, responsible for register. Thefunction entity usually locates in an S-CSCF of the IMS network;

The Registrar may perform operations such as an authentication on theUser Agent. After the authentication is passed, a 200 OK message isreturned to the User Agent, which carries a time length of aregistration timer determined by the network or the shortest and longestrefresh time allowed by the network;

The UE starts a registration timer on the user side according to theindication in the 200 OK message.

When the UE has registered with the network (certainly the UE has notyet registered with the network, but the UE can be configured toinitiate a register request when the capability changes), but when noservice is being processed and before the registration timer on the userside has expired, in case a PnP device is plugged into/unplugged fromthe UE or a built-in function is enabled/disabled (i.e., the userequipment capability changes), the User Agent of UE will be triggeredautomatically or manually to initiate a RE-REGISTER process, whereininformation of a changed capability of the user equipment is carried ina register request message, so that information of the user equipmentcapability is stored/updated in a network node (for example, S-CSCF)responsible for processing the session. The detailed steps are shown asfollows:

stopping a registration timer on the user side set currently when theuser equipment capability changes;

sending a register request message by a user equipment carryinginformation of new user equipment capability to the network;

analyzing, by the network, the register request message, and storing theinformation of new user equipment capability for reference by subsequentestablishment of a session;

stopping a current registration timer on the server side set for theuser equipment;

initiating a new registration timer on the server side for the userequipment;

sending a response message carrying information of the new registrationtimer on the server side to the user equipment (in the embodiment, theresponse message may be a 200 OK message);

resetting the registration timer on the user side based on informationof the new registration timer on the server side in the responsemessage.

Wherein, before the UE initiates the re-register process, it stops theregistration timer on the user side set during the previous register,and the register request message carries the new capability informationof the UE; after the Registrar receives the register request message forregister, if it finds that the registration timer on the server side setlast time has not expired yet and the register request message carriesthe information related to the capability of the UE, it can bedetermined that this re-register is caused by the capability change ofthe UE.

If a network node responsible for processing the session and theRegistrar locate in the same network entity, for example, S-CSCF in theIMS network, the server for example, S-CSCF) directly stores thecapability information of the terminal; if they locate in differentnetwork entities, the Registrar is responsible for forwarding theregister request message to the server (for example, S-CSCF) responsiblefor processing the session to store; the server responsible forprocessing the session may utilize the new capability information of theUE during the session establishment process. The Registrar stops theregistration timer on the server side, returns a response message, forexample a 200 OK message, which carries information of the newconfigured registration timer on the server side or the shortest andlongest refresh time allowed by the network to the User Agent, andfinishes the re-register process. After the UE receives the responsemessage, it resets a registration timer on the user side.

Optionally, if a user has not registered with a network, through its owncustomization, the user may choose to trigger a new register processautomatically when the capability of the UE changes or choose to triggermanually. The implementation is optional. Because a register initiationis commonly determined by a user, not by the UE, it can be set in theUE, and chosen by the user; either the user determines when the registeris initiated, or the register is initiated automatically once each timethe operation on the terminal device by the user results in the changeof the UE capability, and in the latter case, the user knows theregister, so it does not influence the usage. When the register requestmessage carries the newest capability information of the UE, theinformation carried in the message may be a detailed capability value,including all capability information set by the current UE or the changevalue of the UE capability.

In addition, the user equipment can determine whether to inform thenetwork according to the type of the plugged/unplugged device or theenabled/disabled function, and if the capability change of the UE of thecategory needs to be informed, it initiates a re-register or register.This function may be configured by users, or may be a UE's owncapability.

In this way, the function of a re-register is: refreshing a currentregister; responding to the change of the UE's register state; adding anew function; informing the network about information of the changeduser equipment capability.

When the present invention is applied to an IMS network, please refer toFIG. 2, when the capability of the UE has changed, no matter whether theregistration timer on the user side has expired or not, the UE initiatesa re-register process, and stops the registration timer on the serverside set by the previous register, and constructs a new register requestmessage and sends it to a P-CSCF; after the P-CSCF receives the registerrequest message, it does not need to store the new user equipmentcapability information since the P-CSCF may be a proxy CSCF locating ina visited network, but needs to check the validity of the registerrequest message, and forwards it to the S-CSCF after authentication; theS-CSCF, as a control and service execution platform of the IMS session,needs to store the capability information of the UE, which is used asreference information for establishment of a subsequent session, thenthe S-CSCF stops the registration timer on the server side set duringthe previous register and starts a new registration timer on the serverside or returns the shortest and longest refresh time required by thenetwork, and returns a response message, for example a 200 OK message,which carries the time length of the registration timer on the serverside or the shortest and longest refresh time (uniformly called as theinformation of the registration timer) as acknowledgement to the P-CSCF,which is forwarded to the UE by the P-CSCF; the UE resets a newregistration timer on the user side according to the received time afterreceiving the message.

The detailed implementation includes the following steps:

Step S1: when the capability of the UE has changed, no matter whetherthe current registration timer has expired, the UE initiates are-register and stops the registration timer on the server side setduring the previous register, and constructs a new register requestmessage and sends it to a P-CSCF, wherein the message includes publicuser ID, private user ID, domain name of a home network, IP address ofthe UE, and changed capability information of the UE.

Step S2: the P-CSCF determines an access point to the home networkthrough checking domain name of the home network, i.e., I-CSCF, obtainsan address of the access point of the home network through parsing thedomain name, and sends the register request message to the I-CSCF,wherein the main information carried includes: name or address of theP-CSCF, public user ID, private user ID, network ID where the P-CSCFlocates, IP address of the UE, and changed capability information of theUE, etc.

Step S3: the I-CSCF sends a Cx-Query (carried out on Cx interface,inquiring of an address of an S-CSCF serving the user from HSS) messageto an HSS, in which the main information carried includes: public userID, private user ID, network ID where the P-CSCF locates, etc.

Step S4: the HSS finds that the user has registered, and returns anindication showing that a serving S-CSCF has been allocated for theuser, and returns a Cx-Query Resp (a response message to the Cx-Query,which carries the address information of S-CSCF serving the user)message to the I-CSCF.

Step S5: The I-CSCF, using the name of the S-CSCF, shall determine theaddress of the S-CSCF through a name-address resolution mechanism. TheI-CSCF also determines the name of a suitable home network contactpoint, possibly based on information received from the HSS: when thereis no need for network topology hidden function, it is just the S-CSCF;when there is a need for network topology hidden function, it is aI-CSCF having implemented the function. The P-CSCF forwards all thesession signaling to the name of the home network contact point. TheI-CSCF sends the register request message to the S-CSCF, wherein themain information carried includes: name or address of the P-CSCF, publicuser ID, private user ID, network ID where the P-CSCF locates, IPaddress of the UE, and changed capability information of the UE, and anaddress of the I-CSCF implementing the network topology hidden functionif the function is needed.

Step S6: the S-CSCF sends a Cx-Put message (or Cx-Pull message, thefunctions of the two messages are same in the specification, but thespecification defining the two names, and the function of both of themis to request profile information of the served user from HSS by S-CSCFon Cx interface) to HSS, wherein the main information carried includes:public user ID, private user ID, name of S-CSCF, etc. Optionally, if theS-CSCF has already obtained the profile information of the correspondinguser, this step may be omitted.

Step S7: the HSS stores the name of the S-CSCF serving the userspecified in the request message (the request message refers to Cx-Put),and inquires the subscriber information according to user ID, andreturns a Cx-Put Resp (or Cx-Pull Resp) message (a correspondingresponse message, which is used to return the profile information of thespecified user in the request message) as an acknowledgement, whereinthe main information carried includes: user profile information, andsecurity information, etc. Wherein the user profile information is usedwhen the user accesses to various service control platforms.

Step S8: the S-CSCF stores the capability information of the UE receivedfrom the register request message, and according to the capabilityinformation of the UE and considering a filter rule obtained from theuser information, sends a register information to a correspondingservice control platform to execute appropriate service controlprocesses.

Step S9: the S-CSCF returns a 200 OK message to the I-CSCF, wherein themain information carried includes: information of contract point of thehome network, etc. If an I-CSCF with network topology hidden function ischosen in previous steps, the I-CSCF should encrypt the address of theS-CSCF in the information of contact point of the home network.Moreover, the S-CSCF should also re-specify the time length of theregistration timer.

Step S10: the I-CSCF forwards the 200 OK message to the P-CSCF, andreleases all information related to the register;

Step S11, the P-CSCF stores information of contact point of the homenetwork, and forwards the 200 OK message to the UE. After the UEreceives the message, according to the received time length of theregistration timer on the server side, it re-sets the registration timeron the user side;

Subsequently, when the UE is as a called UE, the called S-CSCF candetermine whether to accept a certain service request according to thestored newest capability information of the UE.

Based on the above, the embodiment of the present invention proposes amethod of informing a network of a capability change of the userequipment. Through the use of the present invention, a re-registerprocess can be initiated when the user equipment capability changes byusing an existing register flow and increasing the number of triggerpoints of the re-register process, and therefore the newest capabilitychange of the user equipment can be informed to S-CSCF node(s) in anetwork by the use of the flow, achieving the object of timely informingthe network of a capability change. The S-CSCF in the network will storethe capability information for a subsequent session establishmentprocess, which avoids additional intercommunication messages when aservice session begins a negotiation, shortens intercommunication timerequired by a session establishment, and is convenient to be carriedout.

The forgoing description is only a preferred embodiment of the presentinvention instead of limiting the scope of the invention. It should beapparent to those skilled in the art that various changes, modificationsand substitutions may be made without departing from the principle andspirit of the invention and therefore should be covered and protected bythe scope of the invention as set by the appended claims and itsequivalents.

1. A method of informing a network of a change of user equipmentcapability, comprising: receiving, by a network, a register requestmessage carrying information of new user equipment capability from auser equipment; stopping a current registration timer on the server sideset for the user equipment; initiating a new registration timer on theserver side for the user equipment; and sending a response messagecarrying information of the new registration timer on the server side tothe user equipment.
 2. The method according to claim 1, wherein saidresponse message is a 200 OK message.
 3. The method according to claim1, further comprising: storing, by network nodes responsible forprocessing a session, said information of the new user equipmentcapability.
 4. The method according to claim 1, wherein said informationof the new registration timer on the server side means a new time lengthset by the network for the new registration timer on the server side orthe shortest and longest refresh time allowed by the network.
 5. Themethod according to claim 1, further comprising: determining, by thenetwork, that the register request message is sent due to the userequipment capability change if the register request message carries theinformation of user equipment capability and the current registrationtimer on the server side has not expired.
 6. The method according toclaim 1, wherein said method is triggered automatically when the userequipment monitors a change of the user equipment capability ortriggered manually.
 7. The method according to claim 1, furthercomprising: determining, by a P-CSCF (Proxy-Call Session ControlFunction), an access point of a home network through checking a domainname of the home network; obtaining, by the P-CSCF, an address of theaccess point of the home network through parsing the domain name, andsending, by the P-CSCF, the register request message to the access pointof the home network, wherein the register request message compriseschanged capability information of the user equipment.
 8. The methodaccording to claim 7, further comprising: sending, according to theinformation of the new user equipment capability and considering afilter rule obtained from user information, a register information to acorresponding service control platform to execute appropriate servicecontrol processes.
 9. A method of informing a network of a change ofuser equipment capability, comprising: sending, by a user equipment, aregister request message carrying information of new user equipmentcapability to a network so that the network stops a current registrationtimer on a server side set for the user equipment; and initiates a newregistration timer on the server side for the user equipment; andreceiving, by the user equipment, a response message carryinginformation of the new registration timer on the server side from thenetwork.
 10. The method according to claim 9, further comprising:resetting, by the user equipment, a registration timer on the user sidebased on information of the new registration timer on the server side inthe response message.
 11. The method according to claim 9, wherein saidresponse message is a 200 OK message.
 12. The method according to claim9, wherein said information of the new user equipment capability isstored in network nodes responsible for processing a session.
 13. Themethod according to claim 9, wherein said information of theregistration timer on the server side means a new time length set by thenetwork or the shortest and longest refresh time allowed by the network.14. The method according to claim 9, wherein if the register requestmessage carries the information of user equipment capability and thecurrent registration timer on the server side has not expired, thenetwork determines that the register request message is sent due to theuser equipment capability change.
 15. The method according to claim 9,further comprising: initiating, by the user equipment, a re-register ifcapability of the user equipment has changed, no matter whether theregistration timer on the user side has expired; stopping, by the userequipment, the registration timer on the server side set during aprevious register of the user equipment; constructing, by the userequipment, a new register request message; and sending, by the userequipment, the new register request message to a P-CSCF (Proxy-CallSession Control Function), wherein the new register request messagecomprises changed capability information of the user equipment.
 16. Anapparatus of informing a network of a change of user equipmentcapability, comprising: means for receiving a register request messagecarrying information of new user equipment capability from a userequipment; means for stopping a current registration timer on a serverside set for the user equipment; means for initiating a new registrationtimer on the server side for the user equipment; and means for sending aresponse message carrying information of the new registration timer onthe server side to the user equipment.
 17. The apparatus according toclaim 16, wherein said response message is a 200 OK message.
 18. Theapparatus according to claim 16, further comprising: network nodesresponsible for processing a session, configured to store saidinformation of the new user equipment capability.
 19. The apparatusaccording to claim 16, wherein said information of the registrationtimer on the server side means a new time length set by the network orthe shortest and longest refresh time allowed by the network.
 20. Theapparatus according to claim 16, further comprising: means fordetermining that the register request message is sent due to the userequipment capability change if the register request message carries theinformation of user equipment capability and the current registrationtimer on the server side has not expired.
 21. The apparatus according toclaim 16, further comprising: a P-CSCF (Proxy-Call Session ControlFunction), configured to determine an access point of a home networkthrough checking a domain name of the home network; obtain an address ofthe access point of the home network through parsing the domain name,and send the register request message to the access point of the homenetwork, wherein the register request message comprises changedcapability information of the user equipment.
 22. The apparatusaccording to claim 21, wherein the apparatus is configured to send,according to the information of the new user equipment capability andconsidering a filter rule obtained from user information, a registerinformation to a corresponding service control platform to executeappropriate service control processes.
 23. A user equipment, comprising:means for sending a register request message carrying information of newuser equipment capability to a network so that the network stops acurrent registration timer on a server side set for the user equipmentand initiates a new registration timer on the server side for the userequipment; and means for receiving a response message carryinginformation of the new registration timer on the server side from thenetwork.
 24. The user equipment according to claim 23, furthercomprising: means for resetting a registration timer on the user sidebased on information of the new registration timer on the server side inthe response message.
 25. The user equipment according to claim 23,wherein said response message is a 200 OK message.
 26. The userequipment according to claim 23, wherein said information of theregistration timer on the server side means a new time length set by thenetwork or the shortest and longest refresh time allowed by the network.27. The user equipment according to claim 23, further comprising: meansfor initiating a re-register if capability of the user equipment haschanged, no matter whether the registration timer on the user side hasexpired; means for stopping the registration timer on the server sideset during a previous register of the user equipment; means forconstructing a new register request message; and means for sending thenew register request message to a P-CSCF (Proxy-Call Session ControlFunction), wherein the new register request message comprises changedcapability information of the user equipment.